Protected substrate structure for a field emission dispaly device

ABSTRACT

A protected faceplate structure of a field emission display device is disclosed in one embodiment. Specifically, in one embodiment, the present invention recites a faceplate of a field emission display device wherein the faceplate of the field emission display device is adapted to have phosphor containing wells disposed above one side thereof. The present embodiment is further comprised of a barrier layer which is disposed over the one side of said faceplate which is adapted to have phosphor containing wells disposed thereabove. The barrier layer of the present embodiment is adapted to prevent degradation of the faceplate. Specifically, the barrier layer of the present embodiment is adapted to prevent degradation of the faceplate due to electron bombardment by electrons directed towards the phosphor containing wells.

CROSS REFERENCE TO RELATED APPLICATION

This Application is a Continuation-in-Part of co-pending, commonly-ownedU.S. patent application Ser. No. 09/087,785, filed May 29, 1998, byLearn et al., and entitled “ENCAPSULATED FLAT PANEL DISPLAY COMPONENTS”.

FIELD OF THE INVENTION

The present claimed invention relates to the field of flat paneldisplays. More particularly, the present claimed invention relates tothe “black matrix” of a flat panel display screen structure.

BACKGROUND ART

Sub-pixel regions on the faceplate of a flat panel display are typicallyseparated by an opaque mesh-like structure commonly referred to as amatrix or “black matrix”. By separating sub-pixel regions, the blackmatrix prevents electrons directed at one sub-pixel from beingoverlapping another sub-pixel. In so doing, a conventional black matrixhelps maintain color purity in a flat panel display. In addition, theblack matrix is also used as a base on which to locate structures suchas, for example, support walls. In addition, if the black matrix isthree dimensional (i.e. it extends above the level of the light emittingphosphors), then the black matrix can prevent some of the electrons backscattered from the phosphors of one sub-pixel from impinging on another,thereby improving color purity.

Polyimide material may be used to form the matrix. It is known thatpolyimide material contains numerous components such as nitrogen,hydrogen, carbon, and oxygen. While contained within the polyimidematerial, these aforementioned constituents do not negatively affect thevacuum environment of the flat panel display. Unfortunately,conventional polyimide matrices and the constituents thereof do notalways remain confined within the polyimide material. That is, undercertain conditions, the polyimide constituents, and combinationsthereof, are released from the polyimide material of the matrix. As aresult, the vacuum environment of the flat panel display is compromised.

Polyimide (or other black matrix material) constituent contaminationoccurs in various ways. As an example, thermally treating or heating aconventional polyimide matrix can cause low molecular weight components(fragments, monomers or groups of monomers) of the polyimide material tomigrate to the surface of the matrix. These low molecular weightcomponents can then move out of the matrix and onto the faceplate. Whenenergetic electrons strike the contaminant-coated faceplate,polymerization of the contaminants can occur. This polymerization, inturn, results in the formation of a dark coating on the faceplate. Thedark coating reduces brightness of the display thereby degrading overallperformance of the flat panel display.

In addition to thermally induced contamination, conventional polyimidematrices also suffer from electron stimulated desorption ofcontaminants. That is, during operation, a cathode portion of the flatpanel display emits electrons which are directed towards sub-pixelregions on the faceplate. However, some of these emitted electrons willeventually strike the matrix. This electron bombardment of theconventional polyimide matrix results in electron-stimulated desorptionof contaminants (i.e. constituents or decomposition products of thepolyimide matrix). These emitted contaminants arising from the polyimidematrix are then deleteriously introduced into the vacuum environment ofthe flat panel display. The contaminants emitted into the vacuumenvironment degrade the vacuum, can induce sputtering, and may also coatthe surface of the field emitters.

Furthermore, conventional polyimide matrices also suffer from X-raystimulated desorption of contaminants. That is, during operation, X-rays(i.e. high energy photons) are generated by, for example, electronsstriking the phosphors. Some of these generated X-rays will eventuallystrike the matrix. Such X-ray bombardment of the conventional polyimidematrix results in X-ray stimulated desorption of contaminants (i.e.constituents or decomposition products of the polyimide matrix). Asdescribed above, these emitted contaminants arising from the polyimidematrix are then deleteriously introduced into the vacuum environment ofthe flat panel display. Like electron stimulated contaminants, theseconstituents degrade the vacuum, can induce sputtering, and may alsocoat the surface of the field emitters.

The faceplate of a field emission cathode ray tube requires a conductiveanode electrode to carry the current used to illuminate the display. Aconductive black matrix structure also provides a uniform potentialsurface, reducing the likelihood of electrical arcing. Unfortunately,conventional polyimide matrices are not conductive. Therefore, localcharging of the black matrix surface may occur and arcing may be inducedbetween the cathode and a conventional matrix structure.

Thus, a need exists for a matrix structure which does not deleteriouslyoutgas when subjected to thermal variations. Another need exists for amatrix structure which meets the above-listed need and which does notsuffer from unwanted electron- or photon-stimulated desorption ofcontaminants. Finally, still another need exists for a matrix structurewhich meets both of the above needs and which also achieves electricalrobustness in the faceplate by providing a constant potential surface,which reduces the possibility of arcing.

Additionally, during operation of a field emission display device,electrons are emitted from field emitters located at a cathode portionof the field emission display device. These emitted electrons are thenaccelerated, using a potential field, towards phosphor containing wells.Upon being impinged by the electrons, the phosphors within the phosphorcontaining wells generate light. Unfortunately, a conventional faceplateis subject to degradation when bombarded by electrons which ultimatelyimpinge the faceplate. It is thought that the bombarding electrons breakchemical bonds in the faceplate. The breakage of the chemical bonds thencauses the faceplate to be light absorbing and, hence, is deleterious tothe operation of the field emission display device.

As yet another drawback, electron bombardment of the faceplate may alsocause conventional faceplates to outgas constituents thereof. As anexample, it is desired, in some applications, to use inexpensivehigh-sodium glass for the faceplate. However, electron bombardment ofsuch inexpensive high-sodium glass causes unwanted migration ofcontaminants (e.g. sodium) from the faceplate into the active region ofthe field emission display device. Such migration of contaminants canresult in harmful contamination of sensitive device elements (e.g. fieldemitters).

In addition to degrading the faceplate, electron bombardment can alsodegrade the cathode substrate structure of the field emission displaydevice. This degradation is due to electron bombardment by electronsoriginating from electron emitting structures wherein the electrons arein some way deflected against the cathode substrate structure. As anexample of the drawback associated with electron bombardment of thecathode substrate structure, it is desired, in some applications, to useinexpensive high-sodium glass for the cathode substrate structure.However, electron bombardment of such inexpensive high-sodium glasscauses unwanted migration of contaminants (e.g. sodium) from the cathodesubstrate structure into the active region of the field emission displaydevice. Such migration of contaminants can result in harmfulcontamination of sensitive device elements (e.g. field emitters).

Thus, a need exists for a method and apparatus for preventing electronbombardment and subsequent degradation of a faceplate of a fieldemission display device. A need also exists for a method and apparatusfor preventing electron bombardment and subsequent degradation of acathode substrate structure of a field emission display device. Stillanother need exists for a method and apparatus which prevents themigration of contaminants from a substrate structure (e.g. the faceplateor the cathode substrate structure) into the active region of the fieldemission display device.

SUMMARY OF INVENTION

The present invention provides in one embodiment, a method and apparatusfor preventing electron bombardment and subsequent degradation of afaceplate of a field emission display device. The present inventionfurther provides in one embodiment, a method and apparatus forpreventing electron bombardment and subsequent degradation of a cathodesubstrate structure of a field emission display device. The presentinvention further provides in one embodiment, a method and apparatuswhich prevents the migration of contaminants from a substrate structure(e.g. the faceplate or the cathode substrate structure) into the activeregion of the field emission display device.

Specifically, in one embodiment, the present invention recites afaceplate of a field emission display device wherein the faceplate ofthe field emission display device is adapted to have phosphor containingwells disposed above one side thereof. The present embodiment is furthercomprised of a barrier layer which is disposed over the one side of saidfaceplate which is adapted to have phosphor containing wells disposedthereabove. The barrier layer of the present embodiment is adapted toprevent degradation of the faceplate. Specifically, the barrier layer ofthe present embodiment is adapted to prevent degradation of thefaceplate due to electron bombardment by electrons directed towards thephosphor containing wells.

In another embodiment, the present invention includes a cathodesubstrate structure having a barrier layer disposed thereon. The barrierlayer of the present embodiment is adapted to prevent degradation of thecathode substrate structure. Specifically, the barrier layer of thepresent embodiment is adapted to prevent degradation of the cathodesubstrate structure due to electron bombardment by electrons originatingfrom field emitters of the field emission display device.

These and other objects and advantages of the present invention will nodoubt become obvious to those of ordinary skill in the art after havingread the following detailed description of the preferred embodimentswhich are illustrated in the various drawing figures.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and form a part ofthis specification, illustrate embodiments of the invention and,together with the description, serve to explain the principles of theinvention:

FIG. 1A is a perspective view of a faceplate of a flat panel displaydevice having a matrix structure disposed thereon in accordance with oneembodiment of the present claimed invention.

FIG. 1B is a perspective view of a support structure of a flat paneldisplay device wherein the support structure is to be encapsulated inaccordance with one embodiment of the present claimed invention.

FIG. 1C is a side sectional view of a focus structure of a flat paneldisplay device wherein the focus structure is to be encapsulated inaccordance with one embodiment of the present claimed invention.

FIG. 2 is a side sectional view of the faceplate and matrix structure ofFIG. 1A taken along line A-A wherein the matrix structure has acontaminant prevention structure disposed thereover in accordance withone embodiment of the present claimed invention.

FIG. 3 is a side sectional view of the faceplate and matrix structure ofFIG. 1A taken along line A-A wherein the matrix structure has amulti-layer contaminant prevention structure disposed thereover inaccordance with one embodiment of the present claimed invention.

FIG. 4 is a side sectional view of a contaminant prevention structuredisposed covering a matrix structure and the sub-pixel regions of afaceplate in accordance with one embodiment of the present claimedinvention.

FIG. 5A is a side sectional view of the faceplate and matrix structureof FIG. 2 having a conductive coating disposed thereover in accordancewith one embodiment of the present claimed invention.

FIG. 5B is a side sectional view of the faceplate and matrix structureof FIG. 3 having a conductive coating disposed thereover in accordancewith one embodiment of the present claimed invention.

FIG. 5C is a side sectional view of the faceplate and matrix structureof FIG. 4 having a conductive coating disposed thereover in accordancewith one embodiment of the present claimed invention.

FIG. 6A is a side sectional view of the faceplate and matrix structureof FIG. 1A taken along line A-A wherein the matrix structure has acontaminant prevention structure comprised of a porous material disposedthereover in accordance with one embodiment of the present claimedinvention.

FIG. 6B is a side sectional view of the faceplate and matrix structureof FIG. 1A taken along line A-A wherein the matrix structure has acontaminant prevention structure comprised of a plurality of layers ofporous material disposed thereover in accordance with one embodiment ofthe present claimed invention.

FIG. 6C is a side sectional view of the faceplate and matrix structureof FIG. 6B having a conductive coating disposed thereover in accordancewith one embodiment of the present claimed invention.

FIG. 7A is a side sectional view of the faceplate and matrix structureof FIG. 1A taken along line A-A wherein the matrix structure has acontaminant prevention structure comprised of a layer of porous materialand a layer of non-porous material disposed thereover in accordance withone embodiment of the present claimed invention.

FIG. 7B is a side sectional view of the faceplate and matrix structureof FIG. 7A having a conductive coating disposed thereover in accordancewith one embodiment of the present claimed invention.

FIG. 8 is a side sectional view of the faceplate and matrix structurewherein the matrix structure has a dye/pigment-containing contaminantprevention structure disposed thereover in accordance with oneembodiment of the present claimed invention.

FIG. 9 is a side sectional view of a protected faceplate structure inwhich is shown a faceplate having a barrier layer disposed thereover inaccordance with one embodiment of the present claimed invention.

FIG. 10 is a side sectional view of a protected cathode substratestructure in which is shown a cathode substrate having a barrier layerdisposed thereover in accordance with one embodiment of the presentclaimed invention.

FIG. 11 is a flow chart of steps performed to provide a protectedsubstrate structure in accordance with one embodiment of the presentclaimed invention.

The drawings referred to in this description should be understood as notbeing drawn to scale except if specifically noted.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the preferred embodiments of theinvention, examples of which are illustrated in the accompanyingdrawings. While the invention will be described in conjunction with thepreferred embodiments, it will be understood that they are not intendedto limit the invention to these embodiments. On the contrary, theinvention is intended to cover alternatives, modifications andequivalents, which may be included within the spirit and scope of theinvention as defined by the appended claims. Furthermore, in thefollowing detailed description of the present invention, numerousspecific details are set forth in order to provide a thoroughunderstanding of the present invention. However, it will be obvious toone of ordinary skill in the art that the present invention may bepracticed without these specific details. In other instances, well knownmethods, procedures, and components have not been described in detail soas not to unnecessarily obscure aspects of the present invention.

With reference now to FIG. 1A, a first step used by the presentembodiment in the formation of an encapsulated matrix is shown. Morespecifically, FIG. 1A shows a perspective view of a faceplate 100 of aflat panel display device having a matrix structure 102 coupled thereto.In the embodiment of FIG. 1A, matrix structure 102 is located onfaceplate 100 such that the row and columns of matrix structure 102separate adjacent sub-pixel regions, typically shown as 104.Additionally, in the present embodiment, matrix structure 102 is formedof polyimide material. Although matrix structure 102 is formed ofpolyimide material in the present embodiment, the present invention isalso well suited to use with various other matrix forming materialswhich may cause deleterious contamination. As an example, the presentinvention is also well suited for use with a matrix structure which iscomprised of a photosensitive polyimide formulation containingcomponents other than polyimide.

With reference still to FIG. 1A, matrix structure 102 is a “multi-level”matrix structure. That is, the rows of matrix structure 102 have adifferent height than the columns of matrix structure 102. Such amulti-level matrix structure is shown in the embodiment of FIG. 1A inorder to more clearly show sub-pixel regions 104. The present inventionis, however, well suited to use with a matrix structure which is notmulti-level. Although the matrix structure of the present invention issometimes referred to as a black matrix, it will be understood that theterm “black” refers to the opaque characteristic of the matrixstructure. That is, the present invention is also well suited to havinga color other than black. Furthermore, in the following Figures, only aportion of the interior surface of a faceplate is shown for purposes ofclarity. Additionally, the following discussion specifically refers to ablack matrix which is encapsulated by a contaminant preventionstructure. Although such a specific recitation is found below, thepresent invention is also well suited for use with various otherphysical components of a flat panel display device. Also, although someembodiments of the present invention refer to a matrix structure fordefining pixel and/or sub-pixel regions of the flat panel display, thepresent invention is also well suited to an embodiment in which thepixel/sub-pixel defining structure is not a “matrix” structure.Therefore, for purposes of the present application, the term matrixstructure refers to a pixel and/or sub-pixel defining structure and notto a particular physical shape of the structure.

Referring now to FIG. 1B, a perspective view of a support structure 150adapted to be encapsulated by a contaminant prevention structure inaccordance with one embodiment of the present claimed invention isshown. As will be described below, in great detail, in conjunction witha matrix structure embodiment, in the present embodiment supportstructure 150 is encapsulated by a contaminant prevention structure.That is, the contaminant prevention structure has a physical structuresuch that contaminants originating within support structure 150 areconfined within support structure 150. Thus, the contaminant preventionstructure prevents contaminants which are generated within supportstructure 150 from migrating outside of support structure 150. Inaddition to confining contaminants within support structure 150, thematerial comprising the contaminant prevention structure of the presentinvention does not outgas contaminants when struck by electrons emittedfrom a cathode portion of the flat panel display. Although supportstructure 150 is a wall in the embodiment of FIG. 1B, the presentinvention is also well suited to an embodiment in which the supportstructure is comprised, for example, of pins, balls, columns, or variousother supporting structures.

Referring now to FIG. 1C, a side sectional view of a focus structure 160adapted to be encapsulated by a contaminant prevention structure inaccordance with one embodiment of the present claimed invention isshown. As will be described below, in great detail, in conjunction witha matrix structure embodiment, in the present embodiment focus structure160 is encapsulated by a contaminant prevention structure. That is, thecontaminant prevention structure has a physical structure such thatcontaminants originating within focus structure 160 are confined withinfocus structure 160. Thus, the contaminant prevention structure preventscontaminants which are generated within focus structure 160 frommigrating outside of focus structure 160. In addition to confiningcontaminants within focus structure 160, the material comprising thecontaminant prevention structure of the present invention does notoutgas contaminants when struck by electrons emitted from a cathodeportion of the flat panel display. Although focus structure 160 is awaffle-like structure in the embodiment of FIG. 1C, the presentinvention is also well suited to an embodiment in which the focusstructure has a different shape.

Referring next to FIG. 2, a side sectional view of faceplate 100 andmatrix structure 102 taken along line A-A of FIG. 1A is shown. In theside sectional view, only a portion of matrix structure 102 is shown forpurposes of clarity. It will be understood, however, that the followingsteps are performed over a much larger portion of matrix structure 102and are not limited only to those portion of matrix structure 102 shownin FIG. 2. Additionally, the following steps used in the formation ofthe present invention are also well suited to an approach in which apreliminary bake-out step is used to initially purge some of thecontaminants from the matrix. In a bake-out step, the polyimide matrixis heated prior to placing the polyimide matrix in the sealed vacuumenvironment of the flat panel display.

Referring again to FIG. 2, in one embodiment of the present invention, acontaminant prevention structure 106 is disposed covering matrixstructure 102. In this embodiment, contaminant prevention structure 106is comprised of a layer of substantially non-porous material. That is,matrix structure 102 has a physical structure such that contaminantsoriginating within matrix structure 102 are confined within matrixstructure 102. Thus, contaminant prevention structure 106 preventscontaminants which are generated within matrix structure 102 frommigrating outside of matrix structure 102. In addition to confiningcontaminants within matrix structure 102, the material comprisingcontaminant prevention structure 106 of the present invention does notoutgas contaminants when struck by electrons emitted from a cathodeportion of the flat panel display.

With reference again to FIG. 2, arrow 108 depicts the path of acontaminant generated within matrix structure 102. It will be understoodthat such contaminants include species such as, for example, N₂, H₂,CH₄, CO, CO₂, O₂, and H₂O. As shown by arrow 108, contaminant preventionstructure 106 prevents contaminants from being emitted from matrixstructure 102.

With reference still to FIG. 2, as stated above, in the presentembodiment, contaminant prevention structure 106 is comprised of asubstantially non-porous material. In one embodiment, the substantiallynon-porous material of contaminant prevention structure 106 is selectedfrom the group consisting of: silicon oxide, a metal film, an inorganicsolid, and the like. The present embodiment is also well suited to theuse of material such as aluminum, beryllium, and chemical vapordeposited silicon oxide for non-porous prevention structure 106.Moreover, the present invention is well suited to an embodiment in whichthe material of non-porous prevention structure 106 is a solid with amelting point of greater than approximately 500 degrees Celsius. In oneembodiment, the substantially non-porous material is deposited overmatrix structure 102 by chemical vapor deposition (CVD), evaporation,sputtering, or other means, to a thickness of approximately 50-500nanometers. It will be understood, however, that the present inventionis well suited to the use of various other substantially non-porousmaterials which are suited to confining contaminants within matrixstructure 102. The present invention is also well suited to varying thethickness of contaminant prevention structure 106 to greater than orless than the thickness range listed above.

With reference still to FIG. 2, in one embodiment of the presentinvention, contaminant prevention structure 106 has a thickness which issufficient to prevent penetration by electrons directed towardsfaceplate 100. In one such embodiment, contaminant prevention structure106 is comprised of a layer of silicon dioxide deposited covering matrix102 by CVD, evaporation, sputtering, or other means, to a thickness ofapproximately 100-500 nanometers. As a result, such an embodimentconfines thermally generated contaminants within or on the surface ofmatrix structure 102, and further prevents contaminants from beingformed by electron stimulated desorption. That is, the presentembodiment substantially eliminates a major deleterious conditionassociated with electron bombardment of matrix structure 102. In onesuch embodiment in which the contaminant prevention structure preventspenetration therethrough by electrons, the contaminant preventionstructure does not hermetically seal the underlying component. Althoughsilicon dioxide is specifically recited as the barrier layer material inthe present embodiment, the present invention (including each of theabove-listed embodiments, and each of the below listed embodiments isalso well suited to the use of Al₂O₃, CrOx, ZnO, Si₃N₄, SiO₂, TaO₅, TinOxide, ITO, ZrO₂, Y₂O₃, TiO₂, and MgO and combinations thereof as thebarrier layer material.

With reference next to FIG. 3, in the present embodiment, a multi-layercontaminant prevention structure is disposed covering matrix structure102. In this embodiment, the multi-layer contaminant preventionstructure is comprised of a plurality of layers, 106 and 110, ofsubstantially non-porous material. That is, matrix structure 102 has aphysical structure such that contaminants originating within matrixstructure 102 are confined within matrix structure 102. Thus, thepresent multi-layer contaminant prevention structure preventscontaminants which are generated within matrix structure 102 frommigrating outside of matrix structure 102. In addition to confiningcontaminants within matrix structure 102, layers 106 and 110 comprisingthe multi-layer contaminant prevention structure of the presentinvention do not outgas contaminants when struck by electrons emittedfrom a cathode portion of the flat panel display.

As in the above-described embodiment, arrow 108 depicts the path of acontaminant generated within matrix structure 102. It will be understoodthat such contaminants include species such as, for example, N₂, H₂,CH₄, CO, CO₂, O₂, and H₂O. As shown by arrow 108, the presentmulti-layer contaminant prevention structure prevents contaminants frombeing emitted from matrix structure 102.

With reference still to FIG. 3, as stated above, in the presentembodiment, multi-layer contaminant prevention structure is comprised ofa plurality of layers of substantially non-porous material. In oneembodiment, at least one of the substantially non-porous layers ofmaterial, 106 and 110, of the multi-layer contaminant preventionstructure is selected from the group consisting of: silicon dioxide; ametal film; an inorganic solid, Al₂O₃, CrOx, ZnO, Si₃N₄, SiO₂, TaO₅, TinOxide, ITO, ZrO₂, Y₂O₃, TiO₂, and MgO and combinations thereof and thelike. The present embodiment is also well suited to the use of materialsuch as aluminum, beryllium, and chemical vapor deposited silicon oxidefor at least one of the substantially non-porous layers of material 106and 110. Moreover, the present invention is well suited to an embodimentin which at least one of the non-porous layers of material 106 and 110is comprised of a solid with a melting point of greater thanapproximately 500 degrees Celsius. In one embodiment, at least one oflayers 106 and 110 is deposited over matrix structure 102 by chemicalvapor deposition (CVD), evaporation, sputtering, or other means. In thisembodiment, the multi-layer contaminant prevention structure has a totalthickness of approximately 50-500 nanometers. It will be understood,however, that the present invention is well suited to the use of variousother substantially non-porous materials which are suited to confiningcontaminants within matrix structure 102. The present invention is alsowell suited to varying the total thickness of the multi-layercontaminant prevention structure to greater than or less than thethickness range listed above. Furthermore, the present invention is alsowell suited to varying the number of layers of substantially non-porousmaterial which comprise the multi-layer contaminant preventionstructure.

In this embodiment, the multi-layer contaminant prevention structure hasa thickness which is sufficient to prevent penetration by electronsdirected towards faceplate 100. In one such embodiment, the multi-layercontaminant prevention structure includes a layer of silicon dioxidedeposited covering matrix 102 by CVD to a thickness of approximately100-500 nanometers. As a result, such an embodiment confines thermallygenerated contaminants within matrix structure 102, and further preventscontaminants from being formed by electron stimulated desorption. Thatis, the present embodiment substantially eliminates a major deleteriouscondition associated with electron bombardment of matrix structure 102.

Referring now to FIG. 4, in the present embodiment, a contaminantprevention structure 112 is disposed covering matrix structure 102 andthe sub-pixel regions 114 of faceplate 100. In this embodiment, thesubstantially non-porous material is a transparent material such assilicon dioxide or indium tin oxide which is deposited over matrixstructure 102 and sub-pixel regions 114 by chemical vapor deposition(CVD), evaporation, sputtering, or other means, to a thickness ofapproximately 50-500 nanometers. Although contaminant preventionstructure 112 extends into sub-pixel regions 114, the presence of thesilicon dioxide material in sub-pixel regions 114 does not adverselyaffect the formation or operation of the flat panel display. It will beunderstood, however, that the present invention is well suited to theuse of various other substantially non-porous materials which are suitedto confining contaminants within matrix structure 102 and which do notadversely affect the formation or operation of the flat panel display.The present invention is also well suited to varying the thickness ofcontaminant prevention structure 112 to greater than or less than thethickness range listed above.

In the embodiment of FIG. 4, the contaminant prevention structure 112has a thickness which is sufficient to prevent penetration by electronsdirected towards faceplate 100. Thus, as in the previously describedembodiments, the present embodiment confines thermally generatedcontaminants within matrix structure 102, and further preventscontaminants from being formed by electron stimulated desorption. Thatis, the present embodiment substantially eliminates a major deleteriouscondition associated with electron bombardment of matrix structure 102.

With reference now to FIG. 5A, another embodiment of the presentinvention is shown in which a conductive coating 116 is disposedcovering a contaminant prevention structure 106. (The present embodimentdepicts the embodiment of FIG. 2, having conductive coating 116 disposedthereover.) In the present embodiment, conductive coating is preferablycomprised of a low atomic number material. For purposes of the presentapplication, a low atomic number material refers to a material comprisedof elements having atomic numbers of less than 18. Additionally, a lowatomic number material will reduce the electron scattering compared to ahigh atomic number material. More specifically, in one embodiment,conductive coating 116 is comprised, for example, of a CB800A DAG madeby Acheson Colloids of Port Huron, Mich. In another embodiment,conductive coating 116 is comprised of a carbon-based conductivematerial. In still another embodiment, the layer of carbon-basedconductive material is applied as a semi-dry spray to reduce shrinkageof conductive coating 116. In so doing, the present invention allows forimproved control over the final depth of conductive coating 116.Although such deposition methods are recited above, it will beunderstood that the present invention is also well suited to usingvarious other deposition methods to deposit various other conductivecoatings over contaminant prevention structure 106. For example, thepresent invention is also well suited to the use of an aluminum coatingwhich is applied by an angled evaporation.

As mentioned above, the top surface of matrix structure 102 isphysically closer to the field emitter than is faceplate 100. Byapplying conductive coating 116 over the top surface of matrix structure102, the present embodiment provides a constant potential surface. Byproviding a constant potential surface, the present embodiment reducesthe possibility of potential arcing. As result, the present embodimenthelps to ensure that the integrity of the phosphors and the overlyingaluminum layer (not yet deposited in the embodiment of FIG. 5A) ismaintained. In addition, the conductive encapsulating layer can be mademore electrically or thermally conductive than the aluminum layer overthe phosphor by making it thicker or of a more conductive material,thereby enabling the encapsulating material to readily prevent localizedvoltage spikes by carrying off high electrical currents of potentialarcs and to better physically withstand any arcs that may occur.Furthermore, the conductive coating can be a single layer (as in FIG. 2)on the black matrix and need not be a double layer as drawn.

With reference now to FIG. 5B, another embodiment of the presentinvention is shown in which a conductive coating 116 is disposedcovering layers 106 and 110 of a multi-layer contaminant preventionstructure. (The present embodiment depicts the embodiment of FIG. 3,having conductive coating 116 disposed thereover.) In the presentembodiment, conductive coating is preferably comprised of a low atomicnumber material, or a material comprised predominantly of low atomicnumber elements. For purposes of the present application, a low atomicnumber material refers to a material comprised of elements having atomicnumbers of less than 18. Although such a definition is recited herein,the present application is also well suited to an embodiment in whichthe conductive coating is not comprised of a low atomic number material.More specifically, in one embodiment, conductive coating 116 iscomprised, for example, of a CB800A DAG made by Acheson Colloids of PortHuron, Mich. In another embodiment, conductive coating 116 is comprisedof a carbon-based conductive material. In still another embodiment, thelayer of carbon-based conductive material is applied as a semi-dry sprayto reduce shrinkage of conductive coating 116. In so doing, the presentinvention allows for improved control over the final depth of conductivecoating 116. Although such deposition methods are recited above, it willbe understood that the present invention is also well suited to usingvarious other deposition methods to deposit various other conductivecoatings over layers 106 and 110 of the multi-layer contaminantprevention structure. For example, the present invention is also wellsuited to the use of an aluminum coating which is applied by an angledevaporation.

For the reasons set forth in detail above, the present embodimentprovides a constant potential surface and decreases the chances that anyelectrical arcing will occur. As a result, the present embodiment helpsto ensure that the integrity of the phosphors and the overlying aluminumlayer (not yet deposited in the embodiment of FIG. 5B) is maintained.

With reference now to FIG. 5C, another embodiment of the presentinvention is shown in which a conductive coating 116 is disposed overcontaminant prevention structure 112. (The present embodiment depictsthe embodiment of FIG. 4, having conductive coating 116 disposedthereover.) In the present embodiment, conductive coating is preferablycomprised of a low atomic number material. More specifically, in oneembodiment, conductive coating 116 is comprised, for example, of aCB800A DAG made by Acheson Colloids of Port Huron, Mich. In anotherembodiment, conductive coating 116 is comprised of a carbon-basedconductive material. In still another embodiment, the layer ofcarbon-based conductive material is applied as a semi-dry spray toreduce shrinkage of conductive coating 116. In so doing, the presentinvention allows for improved control over the final depth of conductivecoating 116. Although such deposition methods are recited above, it willbe understood that the present invention is also well suited to usingvarious other deposition methods to deposit various other conductivecoatings over contaminant prevention structure 112. For example, thepresent invention is also well suited to the use of an aluminum coatingwhich is applied by an angled evaporation.

For the reasons set forth in detail above, the present embodimentprovides a constant potential surface and decreases the chances that anyelectrical arcing will occur. As result, the present embodiment helps toensure that the integrity of the phosphors and the overlying aluminumlayer (not yet deposited in the embodiment of FIG. 5C) is maintained.

The above-described embodiments of the present invention have severalsubstantial benefits associated therewith. For example, the presentinvention eliminates deleterious browning and outgassing associated withprior art polyimide based black matrix structures. Additionally, bypreventing contaminants from being emitted by the matrix structure, thepresent invention prevents coating of the field emitters by the releasedcontaminants. Additionally, by reducing the number and energy ofelectrons striking the polyimide, electron desorption of contaminants isreduced. As a result, the present invention extends the life of thefield emitters. As yet an additional advantage, the contaminantprevention structure of the present invention also protects the matrixstructure from potential damage during subsequent processing steps, andelectrical arcs.

Referring next to FIG. 6A, a side sectional view of faceplate 100 andmatrix structure 102 taken along line A-A of FIG. 1A is shown. Asmentioned above, matrix structure 102 is formed of polyimide material inthe present embodiment. The present invention is also well suited to usewith various other matrix forming materials which may cause deleteriouscontamination. As an example, the present invention is also well suitedfor use with a matrix structure which is comprised of a photosensitivepolyimide formulation containing components other than polyimide.Additionally, the present invention is also well suited for use withvarious other physical components such as, for example, supportstructures and/or focus structures.

Referring still to FIG. 6A, in this embodiment of the present invention,a contaminant prevention structure 602 is disposed covering matrixstructure 102 and the sub-pixel regions 114 of faceplate 100. Althoughcontaminant prevention structure 602 extends into sub-pixel or pixelregions 114, the presence of the transparent porous or non-porousmaterial in sub-pixel or pixel regions 114 does not adversely affect theformation or operation of the flat panel display. It will be understood,however, that the present invention is well suited to an embodiment inwhich the porous material of contaminant prevention structure 602 doesnot extend into sub pixel regions 114. In this embodiment, contaminantprevention structure 106 is comprised of a layer of porous material. Inthis embodiment, the porous material comprising contaminant preventionstructure 602 prevents electrons and X-rays generated within the flatpanel display from striking matrix structure 102. Additionally, thematerial comprising contaminant prevention structure 602 of the presentinvention does not outgas contaminants when struck by electrons orX-rays generated within the flat panel display. It will be understoodthat such contaminants include species such as, for example, N₂, H₂,CH₄, CO, CO₂, O₂, and H₂O.

With reference still to FIG. 6A, as stated above, in the presentembodiment, contaminant prevention structure 602 is comprised of aporous material. In one embodiment, the porous material of contaminantprevention structure 602 is selected from the group consisting of:colloidal silica; silicon oxide; and chemical vapor deposited siliconoxide. It will be understood, however, that the present invention isalso well suited to use with various other porous materials such as, forexample, silicon, oxides, nitrides, carbides, diamond, and the like.Moreover, the present invention is well suited to an embodiment in whichthe material of porous contaminant prevention structure 602 is a solidwith a melting point of greater than approximately 500 degrees Celsius.

Referring again to FIG. 6A, in one embodiment, the porous material issilicon dioxide which is deposited over matrix structure 102 byatmospheric pressure physical vapor deposition (APPVD) to a thickness ofapproximately 30-1,000 nanometers. It will be understood, however, thatthe present invention is well suited to the use of various other porousmaterials which are suited to preventing electron and/or X-raypenetration therethrough by electrons and/or X-rays generated in theflat panel display. The present invention is also well suited to anembodiment in which the layer of porous material is applied, forexample, by sputtering, e-beam evaporation, spraying methods,dip-coating methods, and the like. The present invention is also wellsuited to varying the thickness of contaminant prevention structure 602to greater than or less than the thickness range listed above. Morespecifically, at 6 keV, the vast majority of electrons will notpenetrate farther than 600 nanometers into silicon dioxide. At 10 keV,the vast majority of electrons will not penetrate farther than 1,000nanometers into silicon dioxide. Therefore, in the present embodiment,the depth of the porous material comprising contaminant preventionstructure 602 is adjusted so as to ensure that matrix structure 102 isnot bombarded by electrons and/or X-rays generated within the flat paneldisplay.

With reference next to FIG. 6B, in the present embodiment, a multi-layercontaminant prevention structure is disposed covering matrix structure102. In this embodiment, the multi-layer contaminant preventionstructure is comprised of a plurality of layers, 602 and 604, of porousmaterial. As in the embodiment of FIG. 6A, the present embodimentprevents electrons and X-rays generated within the flat panel displayfrom striking matrix structure 102. Additionally, the materialcomprising the contaminant prevention structure of the present inventiondoes not outgas contaminants when struck by electrons or X-raysgenerated within the flat panel display.

With reference still to FIG. 6B, as stated above, in the presentembodiment, multi-layer contaminant prevention structure is comprised ofa plurality of layers of porous material. In one embodiment, at leastone of the layers of porous material, 602 and 604, of the multi-layercontaminant prevention structure is selected from the group consistingof: colloidal silica; silicon oxide; and chemical vapor depositedsilicon oxide. It will be understood, however, that the presentinvention is also well suited to use with various other porous materialssuch as, for example, silicon, oxides, nitrides, carbides, graphite,aluminum, diamond, and the like. Moreover, the present invention is wellsuited to an embodiment in which at least one of the layers of porousmaterial 602 and 604 is a solid with a melting point of greater thanapproximately 500 degrees Celsius.

Referring again to FIG. 6B, in one embodiment, the porous material of atleast one of layers 602 and 604 is silicon dioxide which is depositedover matrix structure 102 by atmospheric pressure physical vapordeposition (APPVD) to a thickness of approximately 30-1,000 nanometers.It will be understood, however, that the present invention is wellsuited to the use of various other porous materials which are suited topreventing electron and/or X-ray penetration therethrough by electronsand/or X-rays generated in the flat panel display. The present inventionis also well suited to an embodiment in which the layer of porousmaterial is applied, for example, by sputtering, e-beam evaporation,spraying methods, dip-coating methods, and the like. The presentinvention is also well suited to varying the thickness of contaminantprevention structure to greater than or less than the thickness rangelisted above. In the present embodiment, the combined depth of thelayers of porous material 602 and 604 comprising the contaminantprevention structure is adjusted so as to ensure that matrix structure102 is not bombarded by electrons and/or X-rays generated within theflat panel display.

With reference now to FIG. 6C, another embodiment of the presentinvention is shown in which a conductive coating 606 is disposed over acontaminant prevention structure. The present embodiment depicts theembodiment of FIG. 6B having conductive coating 606 disposed thereover.The present invention is, however, well suited to an embodiment in whichconductive coating 606 is disposed over, for example, the embodiment ofFIG. 6A. In the present embodiment, conductive coating is preferablycomprised of a low atomic number material. More specifically, in oneembodiment, conductive coating 606 is comprised, for example, of aCB800A DAG made by Acheson Colloids of Port Huron, Mich. In anotherembodiment, conductive coating 606 is comprised of a carbon-basedconductive material. In still another embodiment, the layer ofcarbon-based conductive material is applied as a semi-dry spray toreduce shrinkage of conductive coating 606. In so doing, the presentinvention allows for improved control over the final depth of conductivecoating 606. Although such deposition methods are recited above, it willbe understood that the present invention is also well suited to usingvarious other deposition methods to deposit various other conductivecoatings (e.g. aluminum) over the contaminant prevention structure.Additionally, in the present embodiment, conductive coating 606 isdeposited to a depth of 100-500 nanometers.

For the reasons set forth in detail above, the present embodimentprovides a constant potential surface and decreases the chances that anyelectrical arcing will occur. As result, the present embodiment helps toensure that the integrity of the phosphors and the overlying aluminumlayer (not yet deposited in the embodiment of FIG. 6C) is maintained.

With reference next to FIG. 7A, in the present embodiment, a multi-layercontaminant prevention structure is disposed covering matrix structure102. In this embodiment, the multi-layer contaminant preventionstructure is comprised of a plurality of layers, 702 and 704. In thisembodiment, layer 702 is comprised of a porous material, while layer 704is comprised of a layer of substantially non-porous material. As in theembodiment of FIG. 6A, the present embodiment prevents electrons andX-rays generated within the flat panel display from striking matrixstructure 102. This embodiment further confines thermally generatedcontaminants within matrix structure 102. Additionally, the materialcomprising the contaminant prevention structure of the present inventiondoes not outgas contaminants when struck by electrons or X-raysgenerated within the flat panel display.

With reference still to FIG. 7A, as stated above, in the presentembodiment, the multi-layer contaminant prevention structure iscomprised of a plurality of layers of material. In one embodiment,porous material, 702 of the multi-layer contaminant prevention structureis selected from the group consisting of: colloidal silica; siliconoxide; and chemical vapor deposited silicon oxide. It will beunderstood, however, that the present invention is also well suited touse with various other porous materials such as, for example, silicon,oxides, nitrides, carbides, diamond, and the like. Moreover, the presentinvention is well suited to an embodiment in which at least one of thelayers of material 702 and 704 is a solid with a melting point ofgreater than approximately 500 degrees Celsius.

Referring again to FIG. 7A, in one embodiment, the plurality of layersof material are defined as follows. Layer 702 is comprised of a layer ofindium tin oxide which is deposited to a depth of approximately100-1,000 nanometers. Layer 704 is comprised of a silicon oxide which isdeposited over matrix structure 102 to a thickness of approximately30-1,000 nanometers. It will be understood, however, that the presentinvention is well suited to the use of various other porous andnon-porous materials. The present invention is also well suited to anembodiment in which the layer of porous material is applied, forexample, by sputtering, e-beam evaporation, spraying methods,dip-coating methods, and the like. The present invention is also wellsuited to varying the thickness of the contaminant prevention structureto greater than or less than the thickness range listed above. In thepresent embodiment, the combined depth of the layers of material 702 and704 comprising the contaminant prevention structure is adjusted so as toensure that matrix structure 102 is not bombarded by electrons and/orX-rays generated within the flat panel display.

With reference now to FIG. 7B, another embodiment of the presentinvention is shown in which a conductive coating 706 is disposed over acontaminant prevention structure. The present embodiment depicts theembodiment of FIG. 7A having conductive coating 706 disposed thereover.Specifically, in such an embodiment, layer 702 is comprised of a layerof indium tin oxide which is deposited to a depth of approximately100-1,000 nanometers. Layer 704 is comprised of a silicon oxide which isdeposited over matrix structure 102 to a thickness of approximately30-1,000 nanometers. Layer 706 of this embodiment is comprised of alayer of aluminum which is deposited to a depth of approximately 30-200nanometers. In the present embodiment, the conductive coating ispreferably comprised of a low atomic number material. More specifically,in one embodiment, conductive coating 606 is comprised, for example, ofa CB800A DAG made by Acheson Colloids of Port Huron, Mich. In anotherembodiment, conductive coating 606 is comprised of a carbon-basedconductive material. In still another embodiment, the layer ofcarbon-based conductive material is applied as a semi-dry spray toreduce shrinkage of conductive coating 606. In so doing, the presentinvention allows for improved control over the final depth of conductivecoating 606. Although such deposition methods are recited above, it willbe understood that the present invention is also well suited to usingvarious other deposition methods to deposit various other conductivecoatings (e.g. aluminum) over the contaminant prevention structure.

Referring still to FIG. 7B, in the present embodiment, the contaminantstructure is comprised of two distinct layers of material 702 and 704.In another embodiment, however, the contaminant prevention structure iscomprised of a layer of porous material (e.g. layer 704 of siliconoxide) having non-porous material (e.g. the indium tin oxide of layer702) impregnated therein. That is, the present invention is also wellsuited to an embodiment in which a layer of substantially porousmaterial has substantially non-porous material impregnated therein. Inone such embodiment, the layer of substantially porous material isdeposited as is described above in detail. Additionally, thesubstantially non-porous material is impregnated within the layer ofsubstantially non-porous material by, for example, sputtering, physicalvapor deposition, and the like. Furthermore, the present embodiment isalso well suited to having a conductive coating disposed thereover as isdescribe above in great detail.

Referring now to FIG. 8, a side sectional view of faceplate 100 andmatrix structure 102 taken along line A-A of FIG. 1A is shown. Asmentioned above, matrix structure 102 is formed of polyimide material inthe present embodiment. The present invention is also well suited to usewith various other matrix forming materials which may cause deleteriouscontamination. As an example, the present invention is also well suitedfor use with a matrix structure which is comprised of a photosensitivepolyimide formulation containing components other than polyimide.Additionally, the present invention is also well suited for use withvarious other physical components such as, for example, supportstructures and/or focus structures. In this embodiment, contaminantprevention structure 802 is disposed over matrix structure 102 and intosub-pixel regions 114. Contaminant prevention structure 802 furtherincludes a selectively light absorbing components (e.g. a dye orpigment) typically shown as 804. In one such embodiment, contaminantprevention structure 802 is comprised of silicon oxide doped withdye/pigment material. In so doing, the present embodiment provides acolor filter which enhances display contrast by reducing reflectedambient light. Also, the present embodiment is well suited to having thedye/pigment disposed only in those portions of contaminant preventionstructure 802 which reside above sub-pixel regions 114. The presentembodiment is also well suited to having the dye/pigment disposed in theentire contaminant prevention structure 802.

For the reasons set forth in detail above, the present embodimentprovides a constant potential surface and decreases the chances that anyelectrical arcing will occur. As result, the present embodiment helps toensure that the integrity of the phosphors and the overlying aluminumlayer (not yet deposited in the embodiment of FIG. 7B) is maintained.

Thus, in one embodiment, the present invention provides a matrixstructure which does not deleteriously outgas when subjected to thermalvariations. The present invention also provides an embodiment in which amatrix structure meets the above-listed need and which reduces unwantedelectron stimulated desorption of contaminants. Finally, in anotherembodiment, the present invention provides a matrix structure whichmeets both of the above needs and which also achieves electricalrobustness in the faceplate by providing a constant potential surfacewhich reduces the possibility of potential arcing. Also, it will beunderstood that the conductive matrix structure of the present inventionis applicable in numerous types of flat panel displays.

Referring now to FIG. 9, a side sectional view of a protected faceplatestructure 900 of a field emission display device is shown. In thisembodiment, a faceplate 100 has a barrier layer 902 disposed over oneside thereof. In this embodiment, matrix structure 102 defines phosphorcontaining well (also referred to as sub-pixel regions) which are shownas areas 114. During operation, electrons are emitted from field emitterlocated at a cathode portion, not shown, of the field emission displaydevice. These emitted electrons are then accelerated, using a potentialfield, towards the phosphor containing wells 114. Upon being impinged bythe electrons, the phosphors within phosphor containing wells 114generate light. As mentioned above, a conventional faceplate is subjectto degradation when impinged by the electrons. In the presentembodiment, however, (and as will be discussed in further detail below)barrier layer 902 prevents degradation of faceplate 100 by electronbombardment.

With reference still to FIG. 9, in the present embodiment barrier layer902 is comprised of a substantially transparent, electron-damageresistant material. In the present embodiment, barrier layer 902 isdeposited over faceplate 100 as one of the initial process stepsperformed in the formation of the field emission display device. Thatis, barrier layer 902 of the present embodiment is disposed abovefaceplate 100 prior to the formation of matrix 102, and prior to theformation of phosphor containing wells 114. Although such an order offormation is specifically recited in the present embodiment, the presentinvention is also well suited to varying the order in which the barrierlayer and the various other features of the field emission display arefabricated.

Referring still to FIG. 9, in one embodiment, barrier layer 902 has athickness sufficient to prevent substantial penetration of electronsthrough barrier layer 902 such that the electrons do not impingefaceplate 100. Specifically, in one embodiment, barrier layer 902 iscomprised of silicon dioxide having a thickness of approximately 100nanometers. Although such a specific type of material and thickness ofmaterial is recited in the present embodiment, the present invention iswell suited to the use of various other materials and/or to various(e.g. greater or lesser) thicknesses of material. Moreover, in thepresent embodiment, the combination of material or materials and thethickness thereof provides a barrier layer which does not significantlyreduce the transmission of light through the faceplate, and whichprotects the faceplate from electron bombardment induced degradation.

With reference yet again to FIG. 9, in one embodiment, in addition topreventing substantial impingement of electrons against faceplate 100,barrier layer 902 prevents the migration of contaminants from faceplate100 into the field emission display device. As a result, faceplate 100is no longer a potentially substantial source of contaminants which candamage sensitive features of the field emission display device. Hence,barrier layer 902 enables use of a desirable and inexpensive high-sodiumglass substrate as faceplate 100. Unlike conventional field emissiondisplays in which the sodium of the high-sodium glass is often migrated(due to electron bombardment) into the active region of the fieldemission display device, the present embodiment prevents the migrationof sodium from faceplate 100 into the field emission display device. Inyet another embodiment, in addition to preventing substantialimpingement of electrons against faceplate 100, and in addition topreventing the migration of contaminants from faceplate 100 into thefield emission display device, barrier layer 902 is also electricallyconductive. In so doing, barrier layer 902 can be used to bleed excesscharge from faceplate 100.

Referring now to FIG. 10, a side sectional view of a protected cathodesubstrate structure 1000 of a field emission display device is shown. Inthis embodiment, a cathode substrate 1001 has a barrier layer 1002disposed over one side thereof. In this embodiment, field emitters,typically shown as 1004, are shown disposed above cathode substrate 1001and between focus structure 160. During operation, electrons are emittedfrom field emitters 1004. These emitted electrons are then accelerated,using a potential field, towards phosphor containing wells, not shown.Upon being impinged by the electrons, the phosphors within phosphorcontaining wells generate light. As mentioned above, a conventionalcathode substrate is subject to degradation when impinged by theelectrons which, through, for example, scattering, impact the cathodesubstrate. In the present embodiment, however, (and as will be discussedin further detail below) barrier layer 1002 prevents degradation ofcathode substrate 1001 by electron bombardment.

With reference still to FIG. 10, in the present embodiment barrier layer1002 is comprised of a substantially transparent, electron-damageresistant material. In the present embodiment, barrier layer 1002 isdeposited over cathode substrate 1001 as one of the initial processsteps performed in the formation of the field emission display device.That is, barrier layer 1002 of the present embodiment is disposed abovecathode substrate 1001 prior to the formation of matrix field emitters1004, and prior to the formation of focus structure 160. Although suchan order of formation is specifically recited in the present embodiment,the present invention is also well suited to varying the order in whichthe barrier layer and the various other features of the field emissiondisplay are fabricated.

Referring still to FIG. 10, in one embodiment, barrier layer 1002 has athickness sufficient to prevent substantial penetration of electronsthrough barrier layer 1002 such that the electrons do not impingecathode substrate 1001. Specifically, in one embodiment, barrier layer1002 is comprised of silicon dioxide having a thickness of approximately100 nanometers. Although such a specific type of material and thicknessof material is recited in the present embodiment, the present inventionis well suited to the use of various other materials and/or to various(e.g. greater or lesser) thicknesses of material.

With reference yet again to FIG. 10, in one embodiment, in addition topreventing substantial impingement of electrons against cathodesubstrate 1001, barrier layer 1002 prevents the migration ofcontaminants from cathode substrate 1001 into the field emission displaydevice. As a result, cathode substrate 1001 is no longer a potentiallysubstantial source of contaminants which can damage sensitive featuresof the field emission display device. Hence, barrier layer 1002 enablesuse of a desirable and inexpensive high-sodium glass substrate ascathode substrate 1001. Unlike conventional field emission displays inwhich the sodium of the high-sodium glass is often migrated (due toelectron bombardment) into the active region of the field emissiondisplay device, the present embodiment prevents the migration of sodiumfrom cathode substrate 1001 into the field emission display device. Inyet another embodiment, in addition to preventing substantialimpingement of electrons against cathode substrate 1001, and in additionto preventing the migration of contaminants from cathode substrate 1001into the field emission display device, barrier layer 1002 is alsoelectrically conductive. In so doing, barrier layer 1002 can be used tobleed excess charge from cathode substrate 1001.

With reference now to FIG. 11, a flow chart 1100 of steps performed inaccordance with one embodiment of the present invention is shown. In thepresent, and as described above in conjunction with FIGS. 9 and 10, thepresent embodiment recites a method for protecting a substrate structureof a field emission display device. Specifically, in one embodiment, thepresent invention comprises at step 1102, providing a substratestructure of a field emission display device. Such a substrate structureincludes, for example, faceplate 100 of FIG. 9 or cathode substrate 1001of FIG. 10. Furthermore, the present invention enables the use of ahigh-sodium glass substrate structure for the field emission displaydevice in one embodiment.

Next, at step 1104, the present embodiment recites disposing a barrierlayer over the substrate structure, wherein the barrier layer is adaptedto prevent degradation of the substrate structure due to bombardment byelectrons. As mentioned above, in one embodiment, barrier layer 1002 iscomprised of a substantially transparent, electron-damage resistantmaterial (e.g. silicon dioxide, Al₂O₃, CrOx, ZnO, Si₃N₄, SiO₂, TaO₅, TinOxide, ITO, ZrO₂, Y₂O₃, TiO₂, and MgO and combinations thereof) having athickness (e.g. 100 nanometers) sufficient to prevent substantialpenetration of electrons therethrough. Also, in one embodiment, thebarrier layer prevents the migration of contaminants from the substrateinto the active region. In still another embodiment, the barrier layeris conductive such that it can be used to bleed excess charge from thesubstrate structure.

The foregoing descriptions of specific embodiments of the presentinvention have been presented for purposes of illustration anddescription. They are not intended to be exhaustive or to limit theinvention to the precise forms disclosed, and obviously manymodifications and variations are possible in light of the aboveteaching. The embodiments were chosen and described in order best toexplain the principles of the invention and its practical application,to thereby enable others skilled in the art best to utilize theinvention and various embodiments with various modifications suited tothe particular use contemplated. It is intended that the scope of theinvention be defined by the Claims appended hereto and theirequivalents.

1. A protected faceplate structure of a field emission display device,said protected faceplate structure comprising: a) a faceplate of a fieldemission display device, said faceplate comprising phosphor containingwells disposed above one side thereof; b) an opaque matrix forseparating subpixel regions of said faceplate; and c) a barrier layerdisposed over said opaque matrix and said subpixel regions of saidfaceplate, wherein said barrier layer prevents penetration by electronsdirected towards said faceplate.
 2. The protected faceplate structure ofa field emission display device of claim 1, wherein said faceplate iscomprised of a high-sodium glass substrate.
 3. The protected faceplatestructure of a field emission display device of claim 1, wherein saidbarrier layer is comprised of a substantially transparent,electron-damage resistant material.
 4. The protected faceplate structureof a field emission display device of claim 1, wherein said barrierlayer has a thickness sufficient to prevent substantial penetration ofsaid electrons through said barrier layer such that said electrons donot impinge said faceplate.
 5. The protected faceplate structure of afield emission display device of claim 1, wherein said barrier layer isselected from the group consisting of silicon dioxide, Al₂O₃, CrOx, ZnO,Si₃N₄, SiO₂, TaO₅, Tin Oxide, ITO, ZrO₂, Y₂O₃, TiO₂, and MgO andcombinations thereof.
 6. The protected faceplate structure of a fieldemission display device of claim 5, wherein said barrier layer has athickness of approximately 100 nanometers.
 7. The protected faceplatestructure of a field emission display device of claim 1, wherein saidbarrier layer prevents the migration of contaminants from said faceplateinto said field emission display device.
 8. The protected faceplatestructure of a field emission display device of claim 2, wherein saidbarrier layer prevents the migration of sodium from said faceplate intosaid field emission display device.
 9. The protected faceplate structureof a field emission display device of claim 1, wherein said barrierlayer is electrically conductive.
 10. A protected cathode substratestructure of a field emission display device, said protected cathodesubstrate structure comprising: a) a cathode substrate of a fieldemission display device, said cathode substrate comprising an electronemitting structure disposed above one side thereof, wherein said cathodesubstrate comprises high-sodium glass; and b) a substantially continuousbarrier layer of substantially uniform thickness disposed over said oneside of said cathode substrate, wherein said barrier layer preventselectron bombardment by electrons originating from said electronemitting structure.
 11. (canceled)
 12. The protected cathode substratestructure of a field emission display device of claim 10, wherein saidbarrier layer is comprised of a substantially transparent,electron-damage resistant material.
 13. The protected cathode substratestructure of a field emission display device of claim 10, wherein saidbarrier layer has a thickness sufficient to prevent substantialpenetration of said electrons through said barrier layer such that saidelectrons do not impinge said cathode substrate.
 14. The protectedcathode substrate structure of a field emission display device of claim10, wherein said barrier layer is comprised of silicon dioxide, Al₂O₃,CrOx, ZnO, Si₃N₄, SiO₂, TaO₅, Tin Oxide, ITO, ZrO₂, Y₂O₃, TiO₂, and MgOand combinations thereof.
 15. The protected cathode substrate structureof a field emission display device of claim 14, wherein said barrierlayer has a thickness of approximately 100 nanometers.
 16. The protectedcathode substrate structure of a field emission display device of claim10, wherein said barrier layer prevents the migration of contaminantsfrom said cathode substrate into said field emission display device. 17.The protected cathode substrate structure of a field emission displaydevice of claim 10, wherein said barrier layer prevents the migration ofsodium from said cathode substrate into said field emission displaydevice.
 18. The protected cathode substrate structure of a fieldemission display device of claim 10, wherein said barrier layer iselectrically conductive.
 19. A method for protecting a substratestructure of a field emission display device, said method comprising thesteps of: a) providing a faceplate structure of a field emission displaydevice, said faceplate structure comprising an opaque matrix forseparating subpixel regions of said faceplate structure; and b)disposing a barrier layer over said opaque matrix and over said subpixelregions of said faceplate structure, wherein said barrier layer preventspenetration by electrons.
 20. The method for protecting a substratestructure of a field emission display device as recited in claim 19wherein said substrate structure comprises a faceplate of said fieldemission display device.
 21. The method for protecting a substratestructure of a field emission display device as recited in claim 19wherein said substrate structure comprises a cathode substrate of saidfield emission display device.
 22. The method for protecting a substratestructure of a field emission display device as recited in claim 19wherein step a) comprises providing a high-sodium glass substratestructure for said field emission display device.
 23. The method forprotecting a substrate structure of a field emission display device asrecited in claim 19 wherein step b) comprises disposing said barrierlayer over said substrate structure wherein said barrier layer iscomprised of a substantially transparent, electron-damage resistantmaterial.
 24. The method for protecting a substrate structure of a fieldemission display device as recited in claim 19 wherein step b) comprisesdisposing said barrier layer over said substrate structure such thatsaid barrier layer has a thickness sufficient to prevent substantialpenetration of said electrons therethrough.
 25. The method forprotecting a substrate structure of a field emission display device asrecited in claim 19 wherein step b) comprises disposing a barrier layerover said substrate structure wherein said barrier layer is selectedfrom the group consisting of silicon dioxide, Al₂O₃, CrOX, ZnO, Si₃N₄,SiO₂, TaO₅, Tin Oxide, ITO, ZrO₂, Y₂O₃, TiO₂ and MgO and combinationsthereof.
 26. The method for protecting a substrate structure of a fieldemission display device as recited in claim 25 wherein step b) comprisesdisposing said barrier layer to a thickness of approximately 100nanometers over said substrate structure.
 27. The method for protectinga substrate structure of a field emission display device as recited inclaim 19 wherein step b) comprises disposing said barrier layer oversaid substrate structure wherein said barrier layer prevents migrationof contaminants from said substrate structure into said field emissiondisplay device.
 28. The method for protecting a substrate structure of afield emission display device as recited in claim 19 wherein step b)comprises disposing said barrier layer over said substrate structuresuch that said barrier layer prevents migration of sodium from saidsubstrate structure into said field emission display device.
 29. Themethod for protecting a substrate structure of a field emission displaydevice as recited in claim 19 wherein step b) comprises disposing anelectrically conductive barrier layer over said substrate structure. 30.The protected faceplate structure of a field emission display device ofclaim 1, wherein said barrier layer includes a selectively lightabsorbing component.
 31. The protected faceplate structure of a fieldemission display device of claim 30, wherein said selectively lightabsorbing component is selected from the group consisting of dyes andpigments.
 32. The protected faceplate structure of a field emissiondisplay device of claim 30, wherein each subpixel of said faceplateincludes a different selectively light absorbing component.
 33. Themethod for protecting a substrate structure of a field emission displaydevice as recited in claim 19, wherein said barrier layer includes aselectively light absorbing component.
 34. The method for protecting asubstrate structure of a field emission display device as recited inclaim 33, wherein said selectively light absorbing component is selectedfrom the group consisting of dyes and pigments.
 35. The method forprotecting a substrate structure of a field emission display device asrecited in claim 33, wherein each subpixel of said faceplate includes adifferent selectively light absorbing component.
 36. A protected cathodesubstrate structure of a field emission display device, said protectedcathode substrate comprising: a) a cathode substrate of a field emissiondisplay device, said cathode substrate comprising an electron emittingstructure disposed above one side thereof; and b) a substantiallycontinuous barrier layer of substantially uniform thickness disposedover said one side of said cathode substrate, wherein said barrier layerprevents electron bombardment by electrons originating from saidelectron emitting structure, and wherein said barrier layer is selectedfrom the group consisting of Al₂O₃, CrOx, ZnO, Si₃N₄, SiO₂, TaO₅, TinOxide, ITO, ZrO₂, Y₂O₃, TiO₂, and MgO and combinations thereof.
 37. Theprotected cathode substrate structure of a field emission display deviceof claim 36, wherein said cathode is comprised of a high-sodium glass.38. The protected cathode substrate structure of a field emissiondisplay device of claim 36, wherein said barrier layer is comprised of asubstantially transparent, electron-damage resistant material.
 39. Theprotected cathode substrate structure of a field emission display deviceof claim 36, wherein said barrier layer has a thickness sufficient toprevent substantial penetration of said electrons through said barrierlayer such that said electrons do not impinge said cathode structure.40. The protected cathode substrate structure of a field emissiondisplay device of claim 36, wherein said barrier layer has a thicknessof approximately 100 nanometers.
 41. The protected cathode substratestructure of a field emission display device of claim 36, wherein saidbarrier layer prevents the migration of contaminants from said cathodesubstrate into said field emission display device.
 42. The protectedcathode substrate structure of a field emission display device of claim41, wherein said barrier layer prevents the migration of sodium fromsaid cathode substrate into said field emission display device.